Netherlands Patent Application No. 8203668 (PHN10449) discloses a television signal memory-write circuit of the above-defined type. Therein, the television signal memory circuit in which the television signal is to be entered is used for a field frequency doubling circuit. The distance between horizontal and vertical synchronizing signals measured by the measuring circuit is transferred, after having been made suitable therefor, to a read circuit in order to obtain a corresponding position of horizontal and vertical synchronizing signals upon reading the memory circuit. As a result thereof, the circuit becomes insensitive to the occurrence of irregularities in the synchronizing signal patterns such as they may, for example, occur in synchronizing signal patterns derived from television signals originating from video recorders.
When the memory circuit is used in, for example, a picture portion enlarging circuit or a noise suppression circuit in which optionally field frequency doubling is also applied, it has been found that in a displayed picture annoying phenomena in the form of sudden transients or interruptions in the noise suppression may, however, still occur during the processing of television signals received from video recorders.